In general, radio frequency identification (RFID) involves an exchange of radio frequency (RF) signals between an RFID interrogation system and a mobile RFID device for identification and/or tracking purposes. The RFID interrogation system typically includes a transceiver, which is commonly called an RFID reader, and a controller. When the mobile RFID device, such as an RFID card, moves within range of the RFID reader, the RFID card receives power in a wireless manner from the RFID reader. As the RFID card receives this power, the controller is able to write data to and read data from the RFID card through the RFID reader.
Certain personal wireless devices, such as mobile or cellular telephone devices, can be configured to operate as an RFID card or an RFID reader. Using technologies like Near-Field Communication, mobile device that includes additional radio frequency identification components can operate as both a mobile RFID device and an RFID reader. Typically, an ordinary RFID card or RFID reader cannot determine if a session was conducted with an ordinary card/reader or if it was replaced by an RFID enabled mobile device. Therefore, because the RFID enabled mobile device can emulate the radio emissions of a conventional RFID card or RFID reader, the RFID enabled mobile device can take the place of an RFID building-access card or RFID payment device (i.e., contactless credit card), thereby eliminating the need for a user to carry a separate RFID card altogether.